Stocks: 5 things to know before the open

The holidays are over. The trading week is set to begin. It's go time.

Here are the five things you need to know before the opening bell rings in New York:

1. Euro slump deepens: The euro continues to plunge against the U.S. dollar as concerns intensify that Greece may be forced to leave the eurozone if the country elects a radical, anti-austerity government at the end of the month.

"The euro breached $1.20 overnight, and continues to trade below that important technical level," said Tom Beevers, CEO at StockViews in London.

The euro has been declining as the U.S. dollar strengthens and Europe teeters on the brink of recession and deflation.

2. Oil slides again: Crude futures are slipping by about 1% and are now trading around $52 per barrel. Oil prices were halved last year as the world faced a supply glut.

"Increasing oil production -- particularly from Russia and Iraq -- coupled with fears for weaker global demand, has continued to push oil lower," said Beevers.